Lady Catherine Meyer, who founded a charity to tackle child abduction, called for a single Europe-wide telephone number that parents could ring the moment their child went missing.

The system, similar to the Amber Alert in the United States, would flash the child’s details up on television and motorway signs.

All ports and airports across Europe would also be alerted.

Lady Meyer, wife of Sir Christopher Meyer, the former British ambassador to Washington, said: "I am without a doubt sure that if an Amber Alert was in place when Madeleine McCann went missing she would have been found, without a doubt."

She added that British police were "decades behind" America in terms of acting with speed and efficiency to find missing children.

"Police say child abduction doesn’t happen in Britain, they say 'there are just one or two highlighted cases’, but it does happen here," she said. "It is just not reported properly."

A spokesman for the McCanns said: "Kate and Gerry fully support any effort to increase co-ordination across Europe in the case where a child has gone missing.

"In America they have the Amber Alert system for sending children’s details across the country quickly.

"They welcome anything that can lead to greater co-ordination across Europe that can help to stop other children going missing in the future."

He added: "They know Catherine very well and have had discussion with her about this."The European Commission launched a Europe-wide missing-child hotline number, 116000, in February last year, but so far only Belgium, Denmark, Greece and Portugal have adopted the scheme.

The Commission’s vice-president, Franco Frattini, said he was disappointed with the progress made at a national level.

"Only four member states showed goodwill until now."

Lady Meyer, founder of Parents and Abducted Children Together (Pact), said that since the US Amber Alert system was set up 1996, following the abduction and murder of nine-year-old Amber Hagerman, 393 missing children have been successfully recovered.

Lady Meyer also called for a single body to co-ordinate child abduction across the UK and Europe and for the European Union to take a tougher stance on children abducted abroad by members of their own family.

Lady Meyer’s sons, Alexander and Constantin are now adults.

But in an interiew in 2003 with the Daily Telegraph she said she had seen them for only 25 hours since they were abducted by her former husband Hans-Peter Volkmann nine years earlier.

He defied a court order by keeping them in Germany when they went there on holiday without their mother.

German courts repeatedly denied her access, although she received backing from courts in Britain and France and support from politicians in Europe and the US.

Her legal battle to get access to them cost her £200,000 - she had to sell her flat, lost her job and several times came close to suicide.

She wrote a book about her experience, entitled They Are My Children, Too: A Mother’s Struggle For Her Sons.